Perennial nasturtiums

Perennial nasturtiums typically have attractive, dainty, rounded to deeply lobed leaves. The flowers are often bright yellow, but some species offer different colours. Types of Tropaeolum hookerianum can have yellow or purple flowers, the flowers of T. speciosum are flame red, those of T. azureum are blue and white and T. tricolor flowers are yellow, red and purple.

They like moist but well-drained, moderately fertile soil, and shelter from strong winds. Although perennials, some, like T. peregrinum (canary creeper), are often grown as annuals. Most need to be kept frost-free and are best suited to greenhouses or mild climates, although T. speciosum is a popular perennial species that is hardy throughout most of the UK.

T. speciosum dislikes hot, dry conditions. T. speciosum and T. hookerianum do not grow well in alkaline soil. Many species are frost-tender and may struggle or die if exposed to freezing temperatures, so check the hardiness rating of the species you intend to grow.

Although often grown for its ornamental appeal, the tubers of T. tuberosum (mashua, anu) are edible and have a peppery flavour which is said to improve after cooking and freezing. The flowers and leaves are also edible.